Carburetor for internal combustion engines



Nov. 22, 193 2. c. DAVIDSON 1,338,653

CARBURETOR FOR INTERNAL COMBUSTION ENGINES I Filed March 18, 1929 s 6 G a a a /6/6/4 v /7 v/7 F E E q 5 Z/ 3 I F Ill 3 Z4 e 3 Y Z 6 7/ 7 7 Z 32 36 1 3 L 3/ 3 .36 -54 .36 I i5? 7 f I if; 32 5/ 1 ,5/

I 4/ 4/ I ml 42 F151 FIEA- rm NEYS Patented Nov. 22, 1932 UNITED STATES oLINToN nAvrnson, 035' SAN FRANCISCO, CALIFORNIA GARBURETOR FOR INTERNAL COMBUSTION ENGINES Application filed March. 18, 1929. Serial no. 347,974.,

My invention relates to engines of the internal combustion type and particularly to those engines wherein a relatively heavy liquid fuel is consumed. Engines of this 5 character have been set forth in my copending applicationspserial No..368,209, filed October 31, 1928, and Serial No.. 330,819, filed January 7, 1929, which have since matured respectively'intoPatent No. 1,774,742

datedJune 4, 1929, and Patent No. 1,759,187

. dated May 20, 1930.

As I have alsoset forth in the aforementioned applications, it is the broad object of my invention to enable an internal combustion engine to be operated upon a relatively heavy hydrocarbon fuel while'utilizing the well known Otto or Beau de Rochas cycle. Engines thus operated possess the light weight and cheapnessof manufacture char- 0 acteristic of the Otto cycle engine and are free from the restrictions normallyplaced upon them by the high quality of the fuel required to operate them.

Another object/of my invention is to pro- 7 5 vide an Otto type engine in whichthe air supply is constant with respectto the 1 rate of fuel supply for any one throttlesetting undervarying conditions of load and speed.

Another object of myinvention is to provide an improved means for supplying fuel to an Otto type engine. The invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following description where I'shall outline in full that form of carburetor for an'internal combustion engine of my invention, which I have selected for illustration in the drawing accompanying and forming part of the present specification. In said drawing, I have shown one form of carburetor for internal combustion engineembod-ying my invention, but it is to be understoodthat I do not limit myself to such form since the invention, as

set forth in the claims, may be embodied in a plurality of forms. s V

i In the drawing, to which I have made reference,Fig. 1 is a cross sectional view through the longitudinal axis of the device of my vention.

sively upon Fig.2 is a cross section through the device a of my invention along the line 2-2 of Fig. 1. 1 Fig.v 3 is an end elevation of the device of my invention as indicatedby, thexline 3 3 of Fig. 1. Y

Fig. 4 is a cross section through the. device of my invention as indicated in the line'L-i ofFig.2. Y y

Infits preferred form, the internal 'combu's f tion engine of my invention includesamani fold through which a quantity of air and atomized fuel flows, the flow of air and fuel being maintained substantially constant for any one, setting of the throttle irrespective. of the engine speed. 1 1 In the embodiment of the invention which 'I have chosento disclose in the drawing, ,a manifold 6 is provided which is in communi- V cation with the cylinders of an Ottotype engine. "While this engine is not shown in the drawing it is preferably of the four' stroke Otto cycle type and is proportioned and designed exactly like an engine of similar speed and power ratingnormally operated eXclugasoline or a light hydrocarbon fuel. i

An air conduit body 7 is provided in com munication with the intake manifold 6 and is preferably maintained thereon by means of stud bolts 8. A fuel passage ,9 is provided if within the body 7 and is usually in communication with a suitable force pump capable of delivering a heavy fuel oil to the conduit under a substantially constantpressure which is sufficiently high to effect atomization ofthe .oilupon itsintroduction into the atomizing means which I have indicated generallylat 11. A gage connection l2forindicatingthe oil'pressure' is also provided in communica tion with fuel passage 9. p, To eflect the atomization of the .oil I'ha've. provided a nozzle 14, in communication with the fuel passage'9. having a minute orifice or aperturel6 therein fromwhich the heavy. r fuel.v oil, usually of a gravity between 12.? to i 40 A. P. 'I., may be ejected directly into, the intake manifold 6L I The nozzle is preferably constructed as a separately machined plug screwed into the intake manifold side of the "airconduit body. It is provided with the oppositely tapered bores 17 and 18 to facilitate oil-flow therethrough. A needle valve 19 projects into the nozzle'l l and co-operates with the nozzle bore 17 to provide orifices or apertures of varying extent depending upon the quantity of fuel which it is desired to eject from thenozzle. a a

A spirally threaded thimble 21 is preferably inserted into the nozzle i l-and closely overlies the needle valve 19 to impart a rapid helical motion to the flowing oil as it enters I from j'the fuel passage 9. I The needle valve is preferably adjustable withrespect to the nozzle 14 by means of threaded portion 22 provided upon the lowerportion of the needle valve and bushing 24 suitably retained in the air: conduit body 7. The needle valve, 1 which preferably projects for a considerable distance from extension 26 of the body 7, is

sealed within the extension 26'by means of a packing gland 27 which prevents the pas- ,sage of oil back along the needle valve;

The air conduit body 7 is expediently formedrwith a plurality of air inlet ports 31 thr'ough which enters the air admitted to the 1 manifold. To effect a-regulation of the quantity of air admitted to the manifold in "relation to the quantity of fuel ejected through the nozzle I conveniently position within the air conduit 7 an air valve 32 which'ismaintained upon the needle valve b'ya sleeve 33 extendingv from the air valve. The air valve 32 is retained uponthe needle valve by means of a set screw 34. Air valve 32 is likewise provided with a pluralityof ports 36 which are positioned either to coincide'with ports 31 in the air conduit or to be variedfto admit -fonly the desired lesser quantities of air to I "the intake manifold. 4O

extending end of the needle valve and retained thereon by: means of theset screw l2, serves to accomplish the throttling offthe fuel'and I h air admitted to the manifold; A movement of the lever arm from one position to another The lever arm .41, usually placed upon the causes the needle valve to move into the nozzle and reduces'the quantity of fuel atomized. The movement of the lever arm also occasions the turning of the air valve to reduce the free area provided by the ports in the body 7 and in the air valve, thus'reducing the air flow. Similarly, a movement of the leverarm in'the I opposite dlrection normally results in the entrance of more air and in the atomization-of. a greaterrquantity of fuel, the a1r valve being moved to provide a larger free'area between the valve and the body'and the needle valve fbei ngmovedout of the nozzle to provide a' larger aperture therethru;

111m found it desirable to'provide a regulating system for controlling, thequantity of air admitted to the intake manifold under si e l adthe drawing I have preferably shown apiston varying conditions of engine speed and en- In the embodiment disclosed in ting, any tendency for an increased amount of air to enter into the intake. manifold is oifset by the movement of the piston valve 51 towards the intake manifold in such amanner thatthe free area of the several air ports is decreased. Thequantity of air admitted is thus kept'substantially constant with respect to thequantity of fuel ejected from the nozzles 35 V I andthe tendency to supply a lean mixture to the carburetor is overcome. 1 Likewise,

when the engine isoperating with a'constant throttle setting'at a high speed and under an increasing load, the piston will move aways-m0 from the' intake manifold'as'the speed decreases to permit the entranceof a relatively "constant quantity of air. Theair'drawn into the manifold is thus maintained substantially constant, for anyone position of the needle'a1a5 valve and theair valve, irrespective of the speed of the engine.

; Iclaim:

1. A carburetor comprising abody having an unobstructed induction passage therein, a;-

fuel nozzle in said passage, a valve for controlling said nozzle, a valve forcontrolling air flow through said passage, means for 'mechanically movingsaid valves in unison in both directions between their extremeposi-sgqos tions, and means responsive to pressure in said passage for additionally controlling; air flow through said passage. A

2. A carburetor comprising a cylindrical body bounding an induction, passage, saidbody having air inlet apertures therein, a fuel nozzle in saidpassage, a valve for controlling said nozzle, a cylindrical valve in said body, said valvehaving ports adapted to register with said-apertures for controlling air flow/i into said passage-means for moving said valves simultaneously, and a piston valve movable in accordance with pressure insaid passage and adapted tooverlie said apertures. 126 to control air flowtherethrough. f A i i 3. A carburetor; comprising a body having air inlet apertures and an induction passage therein, a'fuelnozzle'in said passage, a Valve cOOperating'with' said nozzle, a valve for controlling air flow-through said apertures; each of said valves beingadaptedto be moved between two extreme positions thereof, me-

' chanical means for moving saidvalvesjin uni son 111 both directlons betweensaid positionsi fi for controlling simultaneously fuel flow through said nozzle and air flow through said apertures, and means responsive to pressure in said passage for additionally controlling a air flow through said apertures.

In testimony whereof, I have hereunto set my hand.

CLINTON DAVIDSON. 

